The use of advertising in outer space or related to space flight. While there have only been a few examples of successful marketing campaigns, there have been several proposals to advertise in space, some even planning to launch giant billboards visible from the Earth. (Wikipedia)
Or advertise FOR space like Tang. Or, what was that Slim-Jim-looking thing that those lucky astronauts got to eat in space that they tried to convince the rest of us to eat -- you know, for America?? It looked something like #4 on the Bristol Stool Chart.